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Aristolochic acid I (AAI) can cause nephrotoxicity and is characterized by interstitial fibrosis. The C3a/C3aR axis of macrophages and matrix metalloproteinase-9 (MMP-9) play important roles in fibrosis, but whether they are involved in AAI-induced renal interstitial fibrosis and are related remains to be elucidated. In this study, we investigated whether C3a/C3aR axis of macrophages promotes renal interstitial fibrosis by regulating MMP-9 in aristolochic acid nephropathy (AAN). Intraperitoneal injection of AAI for 28 days successfully induced AAN in C57bl/6 mice. The content of C3a in the kidney of AAN mice was increased, and there was a significant distribution of macrophages in the renal tubules. The same results were observed in the in vitro experiment. We also explored the role and mechanism of macrophages after AAI administration in the epithelial–mesenchymal transformation (EMT) of renal tubular epithelial cells (RTECs) and found that AAI could activate the C3a/C3aR axis of macrophages to upregulate p65 expression in macrophages. p65 upregulated MMP-9 expression in macrophages not only directly but also by promoting the secretion if interleukin-6 by macrophages and then activating STAT3 in RTECs. The upregulation of MMP-9 expression could promote the EMT of RTECs. Taken together, our study demonstrated that the AAI-activated the C3a/C3aR axis of macrophages, which induced MMP-9 production, was one of the causes of renal interstitial fibrosis. Therefore, targeting the C3a/C3aR axis of macrophages is an effective therapeutic strategy for the prevention and treatment of renal interstitial fibrosis in AAN. [Display omitted] • Aristolochic acid I activates the C3a/C3aR axis of macrophages in aristolochic acid nephropathy. • Macrophages promote Aristolochic acid nephropathy via the C3a/C3aR/IL-6 pathway. • Upregulated MMP-9 expression accelerates the EMT of RTECs and aggravates renal interstitial fibrosis. [ABSTRACT FROM AUTHOR]

[Display omitted] • Aristolochic acid I promotes the motility of HCC cells. • EMT is involved in aristolochic acid I-induced cell motility. • Aristolochic acid I activates the C3a/C3aR system in HCC cells. • The C3a/C3aR system plays a role in aristolochic acid I-induced HCC cell motility. Aristolochic acid is an established human carcinogen. Previous reports have demonstrated a link between aristolochic acid exposure and liver cancer prevalence in Asia. The C3a/C3AR axis plays an essential role in regulating cancer cell migration and invasion. Here, we focused on the relationship between AA I-induced migration, invasion and epithelial-mesenchymal transition in HCC cells, as well as the possible role of the C3a/C3AR axis in these effects. HCC cells were exposed to different concentrations of AA I for 24 h. Cell migration and invasion abilities were evaluated with wound healing assays and Transwell invasion assays. The protein and mRNA expression levels were detected by western blot, immunofluorescence and quantitative real-time polymerase chain reaction (qRT-PCR) assays. Furthermore, the level of complement component C3a in the cell supernatant was determined by enzyme-linked immunosorbent assay. C3aRA, a C3a receptor antagonist, was used to block the C3a-C3aR axis. The results showed that aristolochic acid I promoted HCC cell invasion and migration. AAI exposure also induced EMT in HCC cells through E-cadherin downregulation and Snail, N-cadherin, and vimentin upregulation. AAI exposure increased the levels of secreted C3a and the expression of C3aR protein and mRNA in HCC cells. We further found that AA I-induced C3a/C3AR activation was involved in these effects. AA I-induced epithelial-to-mesenchymal transition (EMT), cell migration, and invasion were decreased by C3aR inhibition. Overall, our results suggest that AA I induces HCC cell migration and invasion through the EMT process, which is regulated by C3a/C3aR axis activation. [ABSTRACT FROM AUTHOR]

Les phénomènes d'hypersensibilité aux vaccins à ARNm dirigés contre le SARS-CoV-2 sont très rares. Ils peuvent être liés à un mécanisme IgE-dépendant impliquant les PEG contenus dans les vaccins sous forme de liposomes. Une activation directe de la voie classique du complément (CARPA) a été également fortement suspectée. En complément des tests cutanés, des biomarqueurs ont été proposés, en particulier la recherche d'anticorps anti-PEG, le dosage des anaphylatoxines C5a et C3a ou du complexe soluble C5b-9. Les anticorps anti-PEG sont dosables par quelques méthodes non standardisées mais leur présence dans ces réactions n'a pas été confirmée. Il en est de même pour les protéines du complément. L'histamine et la tryptase ont rarement pu être dosées au moment de la réaction et leur augmentation est inconstante selon les études. Une tryptase basale un peu élevée chez certains patients suggère qu'une hyper-alpha-tryptasémie pourrait être impliquée. Le test d'activation des basophiles s'est imposé comme un examen pouvant être utile mais les résultats sont encore difficiles à interpréter en raison de la variabilité des allergènes utilisés : PEG, PEG sous forme de liposomes ou vaccin lui-même. L'absence de positivité des tests cutanés alors que les basophiles sont capables de s'activer en présence du même allergène ex vivo chez certains patients est en faveur, dans ce cas, d'un phénomène non IgE-dépendant. En conclusion, dans l'exploration des réactions immédiates aux vaccins à ARNm contre le SARS-CoV-2, l'importance de la place de marqueurs biologiques nécessite des études complémentaires afin de mieux identifier les acteurs et les mécanismes impliqués. Hypersensitivity to mRNA vaccines directed against SARS-CoV-2 are rare. They may be related to an IgE-dependent mechanism involving PEG contained in vaccines in the form of liposomes. Direct activation of the classical complement pathway (CARPA) has also been strongly suspected. In addition to skin tests, biomarkers have been proposed: anti-PEG antibodies, determination of anaphylatoxins C5a and C3a, or soluble complex C5b-9. Anti-PEG antibodies can be measured by non-standardized in house methods; their presence in post-vaccination reactions against SARS-CoV2 has not been confirmed by all the studies as well as for complement proteins. Mast cell mediators (histamine and tryptase) could rarely be assayed at the time of reaction and their increase is inconstant depending on studies. A slightly elevated baseline tryptase level in some patients suggests that hyper-alphatryptasemia might be involved. A basophil activation test (BAT) can be performed but the results are still preliminary depending on the allergens used: PEG, PEG in the form of liposomes or vaccine itself. The lack of positivity of skin tests in some patients even though basophils are able to be activated in the presence of the same allergen confirms the hypothesis in this case of a possible non-IgE-dependent phenomenon. In conclusion, concerning the exploration of immediate reactions to mRNA vaccines directed against SARS-CoV-2, the place of biological markers requires additional studies in order to better identify the actors and mechanisms involved. [ABSTRACT FROM AUTHOR]

• Aristolochic acid I activates C3a/C3aR system in aristolochic acid nephropathy. • C3a/C3aR system functions as a promoter in Aristolochic acid I induced EMT. • Antagonist of C3aR reverses the process of fibrosis caused by Aristolochic acid I. Previous studies have reported that the complement system is unconventionally activated in many kinds of glomerulonephritis. Multiple complement components participate in the pathogenic process by triggering immune response or other intracellular signaling pathways. Here, we have investigated the role of C3a and its receptor C3aR in aristolochic acid nephropathy (AAN), which, is featured with progressive interstitial fibrosis. Over release of C3a and increased expression of C3aR parallels to the up-regulation of α-SMA and TGF-β1 in AAN, which appeared to promote epithelial-mesenchymal-transition (EMT). To identify the role of complement activation in AAN, we used an inhibitor of C3aR (C3aRA) to block the coupling of C3a to its receptor. Our results confirmed from decreased EMT, the protective effect of C3aRA in cell apoptosis and inflammatory response induced by aristolochic acid I. These results showed that C3a and its receptor C3aR played pathogenic roles in AAN, and renal tubular epithelial cells were potentially pivotal targets of complement activation that could cause pro-fibrotic effects. [ABSTRACT FROM AUTHOR]

• CaCO 3 generated a synergetic effect with CaSO 4 ·2H 2 O in reducing chloride binding capability of C 3 A. • Langmuir isotherm presented a better description for the hydrated blended C 3 A pastes. • The chloride-bearing AFm phases formed were solid solutions with monoclinic and rhombohedral polymorphs. • The polymorphs of the solid solutions depended on the composition of pastes and chloride concentrations. In this study, the impact of CaCO 3 and CaSO 4 ·2H 2 O on chloride binding in hydrated blended C 3 A pastes was investigated. The chloride binding capacity and pH value were obtained through equilibration method, and the phase assemblages were evaluated using XRD and Raman spectroscopy. The results showed that the exposure of the hydrated blended C 3 A pastes to NaCl solutions caused an increase of pH as a result of the chloride binding by the AFm phases. Both CaCO 3 and CaSO 4 ·2H 2 O led to the decrease of chloride binding capacity and pH value, and CaCO 3 was more obvious than CaSO 4 ·2H 2 O on reducing chloride binding capacity. The greater the CaCO 3 content was, the more obvious the reduction was, while most reduction occurred for the CaCO 3 /C 3 A molar ratios less than 0.5. Especially, coupled incorporation of CaCO 3 and CaSO 4 ·2H 2 O caused a significant reduction in chloride binding capacity and pH, with binding capacity of ettringite < carboaluminate hydrates < monosulfoaluminate < C 3 AH 6. The chloride-bearing AFm phases formed after exposure were solid solutions which presented two monoclinic and rhombohedral polymorphs at ambient temperature, and the polymorphs were dependent on the composition of blended C 3 A pastes and chloride concentrations. CaCO 3 whether with CaSO 4 ·2H 2 O or not led to the solid solutions formation with carbonate-AFm as end member. While CaSO 4 ·2H 2 O showed no effect on the constitution of solid solutions, but led to the transformation of polymorphs. [ABSTRACT FROM AUTHOR]

• Human CD4+ T cells exposed to 1,25(OH) 2 D3 secrete α-1-antitrypsin – representing a novel cellular source of this protein. • α-1-Antitrypsin promotes IL-10 secretion by human CD4+ T cells, via direct interaction with complement C3a. • 1,25(OH) 2 D3 is unable to increase IL10 transcription in CD4+ T cells from α-1-antitrypsin-deficient individuals. • Therefore, autocrine α-1-Antitrypsin is required for 1,25(OH) 2 D3-driven IL-10 expression. Studies to identify novel immune-regulatory functions of active vitamin D (1,25(OH) 2 D3) in human CD4+ T cells revealed that 1,25(OH) 2 D3 potently induced expression of the gene SERPINA1 , encoding the anti-protease α-1-antitrypsin. We confirmed α-1-antitrypsin protein expression by 1,25(OH) 2 D3-treated CD4+ T cells, but not in CD8+ T cells or monocytes. α-1-Antitrypsin promotes anti-inflammatory IL-10 synthesis in other immune cell populations. We therefore investigated its immune-regulatory effects in CD4+ T cells. Plasma-derived α-1-antitrypsin drove IL-10 synthesis by CD4+ T cells, which was not dependent on anti-protease activity, but appeared to require a serum-binding factor, since this could not be achieved with recombinant protein. α-1-Antitrypsin is reported to bind complement components, which regulate T cell function. A role for this interaction was therefore probed. Plasma-derived, but not recombinant α-1-antitrypsin contained C3a. Surface Plasmon Resonance and Microscale Thermophoresis demonstrated α-1-antitrypsin binding to C3a. Addition of C3a to CD4+ T cells cultured with recombinant α-1-antitrypsin restored induction of IL-10, whereas neutralisation of C3a abrogated IL-10 induced by plasma-derived α-1-antitrypsin. To interrogate an endogenous role for the α-1-antitrypsin-C3a axis in 1,25(OH) 2 D3-driven CD4+ T cell IL-10 synthesis, we treated cells from healthy or α-1-antitrypsin-deficient individuals (which transcribe SERPINA1 but do not secrete protein) with 1,25(OH) 2 D3. A significant correlation was identified between SERPINA1 and IL10 gene expression in healthy donor CD4+ T cells, which was absent in cells from α-1-antitrypsin-deficient individuals. Therefore, α-1-antitrypsin is required for 1,25(OH) 2 D3-induced IL-10 expression in CD4+ T cells, interacting with C3a to drive IL-10 expression. [ABSTRACT FROM AUTHOR]

Highlights • The response of astrocytes to injury is a major determinant of the outcome after stroke. • In the acute phase, reactive astrocytes are neuroprotective. • In the post-acute and chronic phase, astrocytes act as both positive and negative regulators of neural plasticity. • Modulation of astrocyte function at this later stage appears as an attractive strategy to improve functional outcome. • Astrocyte intermediate filament (nanofilament) proteins may represent the right target for this objective, and the complement system may be at least one of the suitable bullets to hit it. Abstract Stroke is an acute insult to the central nervous system (CNS) that triggers a sequence of responses in the acute, subacute as well as later stages, with prominent involvement of astrocytes. Astrocyte activation and reactive gliosis in the acute stage of stroke limit the tissue damage and contribute to the restoration of homeostasis. Astrocytes also control many aspects of neural plasticity that is the basis for functional recovery. Here, we discuss the concept of intermediate filaments (nanofilaments) and the complement system as two handles on the astrocyte responses to injury that both present attractive opportunities for novel treatment strategies modulating astrocyte functions and reactive gliosis. [ABSTRACT FROM AUTHOR]

Highlights • The impact of complement activation in the intestines is unclear. • Model colon epithelial cells express the C3aR apically. • C3a stimulates increased mRNA of selected chemokines and increased permeability of cell monolayers. • C3aR signals through Gαi to ERK. • These results suggest C3a likely triggers a heightened response leading to inflammation. Abstract Multiple studies have identified that complement becomes activated during inflammation of the intestines yet it is unclear what roles the split complement molecules play. The epithelium, in particular, may be impacted and accordingly, we first discovered that colonic cell lines indeed possess the C5aR. Here we examined whether these cells also possess the C3aR. We determined that T84, HT-29 and Caco2 all possess C3aR mRNA and protein; T84 and HT29 were used to further explore the consequence of C3a binding the C3aR. C3a led to increased mRNA for CXCL2, CXCL8 and CXCL11. Polarized T84 monolayers responded to apically applied C3a with increased CXCL8 mRNA more rapidly than if the C3a was applied basolaterally. Polarized monolayers also increased permeability when treated with C3a. ERK1/2 was activated by C3a and the increase in CXCL8 mRNA was ERK-dependent in both T84 and HT-29. C3a resulted in activation of Gαi, determined by the ERK1/2 signal showing sensitivity to pertussis toxin. The transmembrane signal was further mapped to include Ras and c-Raf. Finally, we show that the C3aR is expressed by primary cells in mouse enteroids. We conclude that complement activation will contribute to the epithelial response during inflammation through C3a binding to the C3aR including by priming the cells to upregulate mRNA for selected chemokines. [ABSTRACT FROM AUTHOR]

Background Human liver cell lines, like HepaRG and C3A, acquire higher functionality when cultured in the AMC-Bio-Artificial Liver (AMC-BAL). The three main differences between BAL and monolayer culture are the oxygenation (40% vs 20%O 2 ), dynamic vs absent medium perfusion and 3D vs 2D configuration. Here, we investigated the background of the differences between BAL-cultures and monolayers. Methods We performed whole-genome microarray analysis on HepaRG monolayer and BAL-cultures. Next, mitochondrial biogenesis was studied in monolayer and BAL-cultures of HepaRG and C3A. The driving forces for mitochondrial biogenesis by BAL-culturing were investigated in representative culture models differing in oxygenation level, medium flow or 2D vs 3D configuration. Results Gene-sets related to mitochondrial energy metabolism were most prominently up-regulated in HepaRG-BAL vs monolayer cultures. This was confirmed by a 2.4-fold higher mitochondrial abundance with increased expression of mitochondrial OxPhos complexes. Moreover, the transcript levels of mitochondria-encoded genes were up to 3.6-fold induced and mitochondrial membrane potential activity was 8.3-fold increased in BAL vs monolayers. Culturing with 40% O 2 , dynamic medium flow and/or in 3D increased the mitochondrial abundance and expression of mitochondrial complexes vs standard monolayer culturing. The stimulatory effect of the BAL culture on mitochondrial biogenesis was confirmed in C3A cells in which mitochondrial abundance increased 2.2-fold with induction of mitochondria-encoded genes. Conclusions and general significance The increased functionality of liver cell lines upon AMC-BAL culturing is associated with increased mitochondrial biogenesis. High oxygenation, medium perfusion and 3D configuration contribute to the up-regulation of the mitochondrial biogenesis. [ABSTRACT FROM AUTHOR]

Constituting a part of the innate immune system, the complement system consists of over 50 proteins either acting as part of a 3-branch activation cascade, a well-differentiated regulatory system in fluid phase or on each tissue, or as receptors translating the activation signal to multiple cellular effector functions. Complement serves as first line of defence against infections from bacteria, viruses and parasites by orchestrating the immune response through opsonisation, recruitment of immune cells to the site of infection and direct cell lysis. Complement is generally recognised as a protective mechanism against the formation of tumours in humans, but is often limited by various resistance mechanisms interfering with its cytotoxic action, now considered as a great barrier of successful antibody-based immunotherapy. However, recent studies also indicate a pro-tumourigenic potential of complement in certain cancers and under certain conditions. In this review, we present recent findings on the possible dual role of complement in destroying cancer, especially if resistance mechanisms are blocked, but also under certain inflammatory conditions—promoting tumour development. [ABSTRACT FROM AUTHOR]

[Display omitted] • The increase in C 3 A content negatively affected the fresh properties. • PCE with medium main and side chain lengths was the most compatible with high C 3 A cement. • PCE with Long side chains was the most incompatible admixture with high C 3 A cement. • The water content variation changed the C 3 A-PCE chain interaction. In this study, the interaction of polycarboxylate ether-based water reducing admixture (PCE) molecule chain length variation with cements having different C 3 A contents and water content was investigated. For this purpose, a total of seven PCEs were synthesized following three different approaches, i.e., the main chain length changed at a constant side chain length, the side chain lengths varied at a constant main chain length, and both main and side chain lengths changed at a similar molecular weight. Paste and mortar mixtures were prepared with the PCEs and CEM I-42.5R type cements containing three different C 3 A contents (3.60%, 6.82%, 9.05%). The effects of above mentioned variables on the rheological properties and compressive strength of the paste/mortar mixtures were determined. The interaction of PCEs with cements having different C 3 A contents was investigated in detail by performing total organic carbon (TOC) and dynamic light scattering (DLS) analyses. The increase in the main and side chain lengths of PCE molecule up to a certain point positively affected the fresh properties of cementitious systems. Beyond a certain point (i.e. when main chain length is higher than 21 k), the increase in main chain length reduced the hydrodynamic diameter of PCE molecules (up to 32%), and decreased the dispersion performance of the admixture. The increment in side chain length (i.e. when side chain length is higher than 2100 g/mole), on the other hand, adversely affected the rheological properties, especially with high C 3 A cements. [ABSTRACT FROM AUTHOR]

Diverse AFm phases are commonly found during the hydration of calcium sulfoaluminate (CSA), Portland (OPC), and calcium aluminate (CAC) cements. Due to the flexibility in their layered double hydroxide (LDH) structure, they are observed in variable single or multi-anion bearing forms, water contents and transient states. When multiple sulfate and carbonate anion sources, in variable compositions, are available during the hydration of cements, the identity, quantity, and stability of the formed AFm phases vary considerably. They may also precipitate as microcrystalline and/or amorphous phases, rendering their detection by X-ray powder diffraction (PXRD) difficult. In this study the AFm phases have been generated through the hydration of tricalcium aluminate (C 3 A) in the presence of sulfate (anhydrite) and carbonate ions (limestone) in various compositions. A multi-technique approach involving solid-state nuclear magnetic resonance spectroscopy (ssNMR), thermogravimetric analysis/differential scanning calorimetry (TGA/DSC) and PXRD has been employed to govern the sequence of hydration reactions, the evolution, structure, and the stability of AFm phases at 1 and 28 days of C 3 A hydration. The results show that the identity and quantity of AFm phases formed vary considerably according to the nature of the anion sources available during the hydration. Hydration products such as crystalline C 3 AH 6 , ettringite and amorphous as well as crystalline/microcrystalline monoanionic AFm phases (monosulfate, monocarbonate, hydroxy-AFm) and bi-anionic phases (hemicarbonate and solid-solutions involving more anions) have been identified and quantified. [ABSTRACT FROM AUTHOR]

Potent ligands for the human complement C3a receptor (C3aR) were developed from the almost inactive tripeptide Leu-Ala-Arg corresponding to the three C-terminal residues of the endogenous peptide agonist C3a. The analogous Leu-Ser-Arg was modified by condensing the serine side chain with the leucine carbonyl with elimination of water to form leucine-oxazole-arginine. Subsequent elaboration with a variety of N-terminal amide capping groups produced agonists as potent as human C3a itself in stimulating Ca 2+ release from human macrophages. Structure–activity relationships are discussed. [ABSTRACT FROM AUTHOR]

An in vitro zymosan-activation of the Complement system, through the lectin and alternative pathways, was performed in pooled human serum over a 24 h time-course. Activation was quantitatively monitored by measuring the concentration of the upper Complement pathway fragment, C3a and the terminal pathway fragment, C5a. Upper Complement showed a maximum activation of 39% and the time-to-maximum activation reduced 8-fold, as a highly non-linear function of the zymosan dose. The C3a:C5a molar ratio rose to a maximum of 1100:1, before terminal pathway activation was initiated; indicating a flux threshold. This threshold appears to be exceeded once more than 31% of C3 molecules are activated. Above this threshold, significant activation of terminal pathway was observed; reducing the molar ratio to 17:1. The C5a/C3a molar ratio was used to determine the terminal pathway activation relative to total Complement activation and ranged from 0.1–0.8%. This depicts upper Complement activation to be 49-fold larger than terminal activation, a figure consistent with the observed density of the membrane attack complex in the membrane of cells. Our results thus indicate that the relative activity of opsonisation is ~ 50-fold greater than membrane attack complex formation, in vitro, in the pooled serum phenotype. The results suggest a potential clinical application, where an in vitro analysis of a patient on admission, or prior to a surgical procedure, would indicate their upper Complement activation capacity, with activation of C3 measured thereafter, or post-operatively. A patient with an exhausted upper Complement capacity may be vulnerable to infections and complications, such as sepsis. [ABSTRACT FROM AUTHOR]

Objective : Inhibition of components of the complement system or of its receptors has been postulated as a concept for primary and secondary prevention in atherosclerosis and was applied in clinical trials. Although the anaphylatoxin-receptors C3aR and C5aR are commonly associated with inflammatory cells, in vitro studies suggested their expression also on platelets. Methods and Results : Expression levels of C3aR and C5aR were measured by flow cytometry in a collective of 302 patients with documented coronary artery disease (CAD) including patients with stable CAD (n = 152), unstable angina (n = 54), acute myocardial infarction (AMI; Non-ST elevation myocardial infarction, n = 70, ST elevation MI, n = 26) or healthy controls (n = 21). Patients with stable CAD, unstable angina or AMI had significantly higher expression of C5aR on platelets in comparison to healthy controls (MFI 14.68 (5.2), 14.56 (5.18) and 13.34 (4.52) versus 10.68 (3.1)); p < 0.001). In contrast, the expression of C3aR on platelets was significantly enhanced in patients with stable and unstable CAD but not in patients with AMI compared to controls. While there was a strong correlation between the soluble ligands of these receptors C3a and C5a, we observed only a weak correlation with their receptors on platelets. Similarly, agonist induced aggregation (MEA, ADP, and TRAP) showed only a weak correlation with the expression level of anaphylatoxin – receptors on platelets. Of note, the expression of both anaphylatoxin-receptors on platelets strongly correlated with platelet activation as assessed with the surface activation marker P-selectin (r = 0.47, p > 0.001 for C3aR, r = 0.76 for C5aR, p < 0.001). Likewise, we observed a positive correlation of C3aR with other molecules associated with platelet activation such as SDF-1. Conclusion : In summary, we observed a positive correlation between the expression of anaphylatoxin-receptors C3aR and C5aR with platelet activation in patients with CAD. Further investigations are needed to study the clinical and mechanistic relevance of these findings. [ABSTRACT FROM AUTHOR]

This research studied the hydration of C 3 S-C 3 A-calcium sulfate systems made of combinations of two C 3 S (pure triclinic and Al-doped monoclinic), two C 3 A (pure cubic C 3 A and Na-doped orthorhombic), and two calcium sulfates (gypsum and hemihydrate). For each system, the hydration of four different SO 3 contents (0.25–2.0 wt%) was assessed by calorimetry. The optimum SO 3 content was fixed from calorimetry results, and the mixtures were evaluated by in-situ XRD and TGA. The type of C 3 S was the factor that most affected the sulfate balance of the systems. The mixes with Al-C 3 S produced a higher amount of ettringite in the first hours, resulting in much earlier sulfate depletions when compared to the mixes with pure C 3 S. The mixes with ort-C 3 A also showed faster sulfate depletion due to its higher reactivity compared with cb-C 3 A. Finally, the replacement of gypsum by hemihydrate resulted in faster sulfate depletion caused by the faster hemihydrate dissolution. [ABSTRACT FROM AUTHOR]

Osteoarthritis (OA) affects more than 500 million people worldwide and is among the five diseases in Germany causing the highest suffering of the patients and cost for the society. The quality of life of OA patients is severely compromised, and adequate therapy is lacking owing to a knowledge gap that acts as a major barrier to finding safe and effective solutions. Chronic, low-grade inflammation plays a central role in OA pathogenesis and is associated with both OA pain and disease progression. Innate immune pathways, such as the complement- and pattern-recognition receptor pathways, are pivotal to the inflammation in OA and key components of the innate immune system implicated in OA include DAMP-TLR signaling, the complement system, carboxypeptidase B (CPB), and mononuclear cells. Anaphylatoxins C3a and C5a are small polypeptides (77 and 74 amino acids, respectively) which are released by proteolytic cleavage of the complement components C3 and C5. The alternative complement pathway seems to play a crucial role in OA pathogenesis as these complement components, mostly C3 and its activation peptide C3a, were detected at high levels in osteoarthritic cartilage, synovial membrane, and cultured chondrocytes. Targeting the complement system by using anti-complement drugs as a therapeutic option bears the risk of major side effects such as increasing the risk of infection, interfering with cell regeneration and metabolism, and suppressing the clearance of immune complexes. Despite those adverse effects, several synthetic complement peptide antagonists show promising effects in ameliorating inflammatory cell responses also in joint tissues. • Chronic, low-grade inflammation is crucial for OA pathogenesis. • Activation of the complement system occurs already in early stages of OA. • Different cell types in OA joints express and locally secrete complement components. • C3a and C5a are small complement polypeptides involved in OA progression. • New complement-mediating therapeutics could dampen pain and joint degradation in OA. [ABSTRACT FROM AUTHOR]

Amyotrophic lateral sclerosis (ALS) is a fatal neurodegenerative disease, characterized by the progressive loss of motor neurons within the central nervous system. Neural degeneration and inflammatory processes, including activation of the complement system are hallmarks of this pathology. Our past work in ALS animal models (hSOD1 G93A rodents) has revealed that blockade of the receptor for complement activation fragment C5a (C5aR), improves ALS-like symptoms and extends survival. We now show that the levels of C5a and C5b-9, but not C3a nor C4a, are significantly elevated in plasma from ALS patients compared to healthy controls. C5a was also elevated within leukocytes from ALS patients suggesting heightened C5a receptor interaction. Overall, these findings indicate that there is enhanced peripheral immune complement terminal pathway activation in ALS, which may have relevance in the disease process. [ABSTRACT FROM AUTHOR]

Trichloroethylene (TCE) is a major occupational health hazard and causes occupational medicamentosa-like dermatitis (OMLDT) and liver damage. Recent evidence suggests immune response as a distinct mode of action for TCE-induced liver damage. This study aimed to explore the role of the key complement activation product C3a and its receptor C3aR in TCE-induced immune liver injury. A mouse model of skin sensitization was induced by TCE in the presence and absence of the C3aR antagonist SB 290157. Liver function was evaluated by alanine aminotransferase (ALT) and aspartate aminotransferase (AST) in conjunction with histopathological characterizations. C3a and C3aR were detected by immunohistochemistry and C5b-9 was assessed by immunofluorescence. IFN-γ and IL4 expressions were determined by flow cytometry and ELISA. The total sensitization rate was 44.1%. TCE sensitization caused liver cell necrosis and inflammatory infiltration, elevated serum ALT and AST, expression of C3a and C3aR, and deposition of C5b-9 in the liver. IFN-γ and IL-4 expressions were up-regulated in spleen mononuclear cells and their serum levels were also increased. Pretreatment with SB 290157 resulted in more inflammatory infiltration in the liver, higher levels of AST, reduced C3aR expression on Kupffer cells, and decreased IL-4 levels while IFN-γ remained unchanged. These data demonstrate that blocking of C3a binding to C3aR reduces IL4, shifts IFN-γ and IL-4 balance, and aggravates TCE-sensitization induced liver damage. These findings reveal a novel mechanism whereby modulation of Th2 response by C3a binding to C3a receptor contributes to immune-mediated liver damage by TCE exposure. [ABSTRACT FROM AUTHOR]

Highlights: [•] The Cr leaching content of Cr-doped C3A was higher than hydrated C3A matrix in Cr(NO3)3 solution. [•] Part of Cr3+ was oxidized to Cr6+ in the clinkering process and identified as Ca4Al6O12CrO4. [•] The oxidant Cr3+ to Cr6+ resulted in the higher leaching of hydrated matrix of Cr-doped C3A. [ABSTRACT FROM AUTHOR]

Highlights: [•] Both T cell-derived C3 activation fragments C3a and C3b are required for human Th1, but not Th2 responses. [•] The exact C3aR and CD46 complement-mediated pathways are clearly distinct. [•] Working with appropriate patient cells is an invaluable tool for the better understanding of complement's impact on adaptive immunity. [•] Complement is a driver of immune responses, also involved in its contraction with important contribution in immune homeostasis. [ABSTRACT FROM AUTHOR]

Highlights: [•] We systematically examined the three complement pathways during NMO remission. [•] Although the complement pattern is altered in the plasma, activation is unlikely. [•] Alterations suggest the influences of both the disease process and therapy. [•] Systemic complement studies might be of diagnostic value in NMO. [ABSTRACT FROM AUTHOR]

Abstract: In proteinuric nephropathy, epithelial-to-mesenchymal transition (EMT) is an important mechanism that causes renal interstitial fibrosis. The precise role of EMT in the pathogenesis of fibrosis remains controversial, partly due to the absence of suitable in vitro or in vivo models. We developed two microfluidic and compartmental chips that reproduced the fluidic and three-dimensional microenvironment of proximal tubular epithelial cells in vivo. Using one microfluidic device, we stimulated epithelial cells with a flow of healthy human serum, heat-inactivated serum and complement C3a, which mimicked the flow of urine within the proximal tubule. We observed that epithelial cells exposed to serum proteins became apoptotic or developed a mesenchymal phenotype. Incubating cells with C3a induced similar features. However, cells exposed to heat-inactivated serum did not adopt the mesenchymal phenotype. Furthermore, we successfully recorded the cellular morphological changes and the process of transmigration into basement membrane extract during EMT in real-time using another three-dimensional microdevice. In conclusion, we have established a cell-culture system that mimics the native microenvironment of the proximal tubule to a certain extent. Our data indicates that EMT did occur in epithelial cells that were exposed to serum proteins, and C3a plays an essential role in this pathological process. [Copyright &y& Elsevier]

Characterisation of cement clinkers is a prerequisite to optimise properties of cements and concretes. Therefore, the protocol to prepare and characterise cement clinkers using electron backscatter diffraction (EBSD) in combination with energy dispersive X-ray spectrometry (EDS) is described. It is shown that argon broad ion beam polishing delivers surfaces with high contrast electron backscatter diffraction patterns (EBSP). EBSD data quality in high and low vacuum SEM reveals that high vacuum conditions and state-of-the-art EBSD cameras deliver EBSPs of cement clinker at improved quality. Furthermore, exemplary EBSD-EDS analysis is discussed for two Portland cement clinkers. Results clearly show that differentiation between major phases can reliably be achieved. In addition, it is revealed that crystal distortion in belite is high. Analysis of C 3 A phases show that differentiation of orthorhombic and cubic polymorph is possible, and that Mg incorporation leads to amorphization. Results demonstrate that EBSD-EDS analysis allows reliable phase characterisation of cement clinkers. [Display omitted] • Improved EBSP pattern quality by improved sample preparation and application of state-of-the art EBSD detectors (CMOS-based). • High resolution EBSD-EDS mapping showing the fine structure of cement clinker phases, for example belite twin lamella. • EBSD-EDS mapping data allows quantification of microstructural features such as crystal sizes and crystal distortion • A Set of recommendations how to obtain and analyse EBSD-EDX data for cement clinkers is given. [ABSTRACT FROM AUTHOR]

Highlights: [•] Complement activation is critical for hypertension caused by reduced placental blood flow. [•] Inhibiting complement activation with sCR1 attenuates placental ischemia-induced hypertension. [•] Role of complement in placental ischemia-induced hypertension does not depend on VEGF. [•] Inhibiting complement activation may offer a therapeutic avenue in preeclampsia. [ABSTRACT FROM AUTHOR]

Abstract: Interplay between complement factors, regulatory proteins, anaphylatoxins and cytokines could be involved in tendon healing and scar formation. The expression and regulation of complement factors by cytokines or anaphylatoxins are completely unclear in tendon. Hence, the gene expression of the anaphylatoxin receptors C3aR, C5aR and cytoprotective complement regulatory proteins (CRPs) was analysed in human tendon, cultured primary tenocytes and to directly compare the general expression level, additionally in human leukocytes. Time-dependent regulation of complement by cytokines and the anaphylatoxin C3a was assessed in cultured tenocytes. Gene expression of the anaphylatoxin receptors C3aR, C5aR and the CRPs CD46, CD55 and CD59 was detected in tendon, cultured tenocytes and leukocytes, whereas CD35 could only be found in tendon and leukocytes. Compared with cultured tenocytes, complement expression was higher in tendon and compared with leukocytes C3aR, C5aR, CD35 and CD55, but not CD46 and CD59 gene expression levels were lower in tendon. C3aR mRNA was up-regulated by both TNFα and C3a in cultured tenocytes in a time-dependent manner whereby C5aR gene expression was only induced by C3a. IL-6 or C3a impaired the CRP gene expression. C3a stimulation lead to an up-regulation of TNFα and IL-1β mRNA in tenocytes. Degenerated tendons revealed an increased C5aR and a reduced CD55 expression. The expression profile of the investigated complement components in tendon and cultured tenocytes clearly differed from that of leukocytes. Tenocytes respond to the complement split fragment C3a with CRP suppression and enhanced pro-inflammatory cytokine gene expression suggesting their sensitivity to complement activation. [Copyright &y& Elsevier]

Abstract: Our understanding of the complement system has markedly evolved from its early beginnings as a protein system merely detecting and tagging a pathogen for further clearance. For example, the repertoire of danger that complement recognizes covers currently a wide range of distinct self and non-self danger signals. Further, complement is now firmly established as instructor of adaptive B and T cell immunity. This review focuses on two the recent emerging paradigms in the field. Firstly, that complement is not only vitally required for the induction of Th1 immunity but also for the timely contraction of this protective response and therefore for prevention of autoimmunity and immune homeostasis. Secondly, that local rather than systemic complement is impacting on immunemodulation during a T cell response. [Copyright &y& Elsevier]

Abstract: Anaphylatoxins are a group of small peptides (i.e. C3a, C4a and C5a) generated by complement activation and play important roles in innate immunity through the initiation and regulation of inflammatory responses. More recent studies have revealed that, in addition to their traditional roles in inflammation, anaphylatoxins also significantly influence the adaptive immune response. It does so through a number of mechanisms and by targeting various cells. One important mechanism is that anaphylatoxins (C3a, C5a) act on their receptors expressed on innate immune cells such as dendritic cells. This modulates cell activation and their functions in initiating and regulating T cell responses and thus influencing T cell immunity. This review provides an overview of anaphylatoxins in adaptive immune regulation focusing on their roles in modulating dendritic cell and macrophage functions and the importance of local production of complement in this regulation. [Copyright &y& Elsevier]

Abstract: Anaphylatoxins C3a and C5a are important modulators for dendritic cell activation and function in mice. In order to verify the significance of these observations in man, we have investigated the functional modulation of human monocytes derived DCs by C3a and C5a. Here we report that engagement of C3aR or C5aR on human monocytes derived DCs (moDCs) enhances the cell activation and their capacity for allostimulation. In addition, we show that intracellular production of cAMP is reduced and PI3K/AKT, ERK and NF-κB signalling is increased following stimulation with C3a or C5a, identifying intracellular signalling pathways that could convert cell surface C3aR and C5aR engagement into changes in moDC functions. Our data provide evidence that human DCs are equipped to react to C3a/C5a and undergo phenotypic change as well as functional modulation. Complement offers a potential route to modulate human DC function and regulate T cell mediated immunity. [Copyright &y& Elsevier]

Abstract: A recombinant complement anaphylatoxin, C4a, inhibited chemotaxis, respiratory burst and histamine release in mast cell-like HMC-1 cells that were treated with recombinant C5a anaphylatoxin. C4a also inhibited histamine release from HMC-1 cells that were induced by recombinant C3a. The inhibition of C5a- and C3a-induced leukocyte reactions by C4a was recapitulated in peripheral blood CD133+ cell-derived differentiated mast cells. In HMC-1 cells, C4a inhibited cytoplasmic Ca2+ influx, an event that precedes anaphylatoxin-induced chemotactic and secretary responses. A conditioned medium of HMC-1 cells after shortly treated with C4a also inhibited the anaphylatoxin-induced Ca2+ influx even after removal of C4a, indicating that the effect of C4a is to liberate an autocrine inhibitor from the mast cells. The inhibitor secretion by C4a was prevented with pertussis toxin or with a phosphodiesterase inhibitor. Conversely, an adenylyl cyclase inhibitor reproduced the effect of C4a. C4a decreased the intracellular cyclic AMP concentration of HMC-1 cells, indicating that C4a elicited the Gi protein-adenylyl cyclase inhibition pathway. Neither C4a nor the conditioned medium, however, inhibited Ca2+ influx and respiratory burst in C5a- or C3a-stimulated peripheral neutrophils, suggesting that these cells lack this inhibitory system. Additionally, in HMC-1 cells, C4a did not inhibit Ca2+-independent, Leu72Gln-C5a-stimulated chemotactic response. In agreement with this finding, C4a treatment inhibited ERK1/2 phosphorylation in HMC-1 cells stimulated with other anaphylatoxins but did not inhibit p38MAPK phosphorylation in cells stimulated with Leu72Gln-C5a. Taken together, these findings suggest that the autocrine inhibitory effect elicited by C4a is attributed to interruption of Ca2+-dependent intracellular signaling pathway. [Copyright &y& Elsevier]

Abstract: Although human mast cells express G protein coupled receptors for the anaphylatoxin C3a, previous studies indicated that C3a causes mast cell degranulation, at least in part, via a C3a receptor-independent mechanism similar to that proposed for polycationic molecules such as compound 48/80. The purpose of the present study was to delineate the receptor specificity of C3a-induced degranulation in human mast cells. We found that C3a, a C3a receptor “superagonist” (E7) and compound 48/80 induced Ca2+ mobilization and degranulation in a differentiated human mast cell line, LAD2. However, C3a and E7 caused Ca2+ mobilization in an immature mast cell line, HMC-1 but compound 48/80 did not. We have previously shown that LAD2 cells express MrgX1 and MrgX2 but HMC-1 cells do not. To delineate the receptor specificity for C3a and compound 48/80 further, we generated stable transfectants expressing MrgX1 and MrgX2 in a rodent mast cell line, RBL-2H3 cells. We found that compound 48/80 caused degranulation in RBL-2H3 cells expressing MrgX1 and MrgX2 but C3a did not. By contrast, E7 activated RBL-2H3 cells expressing MrgX2 but not MrgX1. These findings demonstrate that in contrast to previous reports, C3a and compound 48/80 do not use a shared mechanism for mast cell degranulation. It shows that while compound 48/80 utilizes MrgX1 and MrgX2 for mast cell degranulation C3a does not. It further reveals the novel finding that the previously characterized synthetic peptide, C3a receptor “superagonist” E7 activates human mast cells via two mechanisms; one involving the C3a receptor and the other MrgX2. [Copyright &y& Elsevier]

Abstract: The role of the complement cascade in the pathophysiology of cerebral arteriovenous malformation (AVM) is largely undefined. Complement subcomponents, C3a and C5a, are potent anaphylatoxins and key mediators of immuno-inflammatory response. Complement activation may contribute to the pro-inflammatory state observed in AVM. Thus, we sought to determine the systemic levels of C3a and C5a and their response to treatments in patients with AVM. Blood samples of 18 patients undergoing treatment for unruptured AVM, and from 30 healthy control participants, were obtained at four times: (i) pre-treatment, (ii) 24-hours post-embolization, (iii) 24-hours post-resection, and at 1-month follow-up. Plasma concentrations of C3a and C5a were measured using enzyme-linked immunosorbent assay. The pre-treatment mean plasma C3a level was significantly higher in patients with AVM (1817±168ng/mL) compared to controls (1126±151ng/mL). The mean C3a level decreased 24-hours after embolization (1482±170ng/mL) and remained at statistically similar levels 24-hours after resection (1511±149ng/mL) and at 1-month follow-up (1535±133ng/mL). Mean C3a levels at the three time points were higher than control levels.The baseline mean plasma C5a level was significantly elevated in patients with AVM (13.1±2.2ng/mL) compared to controls (3.9±1.5ng/mL).Mean C5a level decreasedpost-embolization (8.2±2.3ng/mL) and remained at similar levels post-resection (8.5±3.0ng/mL) and at 1-month follow-up (7.7±2.9ng/mL). Mean C5a levels at the three time points were significantly higher than the control levels. We conclude that systemic C3a and C5a levels in patients with AVM are elevated at baseline, decrease significantly after embolization, and remain at the new baseline levels after surgery and 1-month follow-up. [Copyright &y& Elsevier]

Abstract: Allergic diseases such as asthma result from inappropriate immunologic responses to common environmental allergens in genetically susceptible individuals. Following allergen exposure, interaction of dendritic cells (DC) with CD4+ T cells leads to the production of Th2 cytokines, which induce B cells to synthesize IgE molecules (sensitization phase). These IgE molecules bind to their high affinity receptors (FcɛRI) on the surface of mast cells and basophils and their subsequent cross-linking by allergen results in the release of preformed and newly synthesized mediators, which cause bronchoconstriction, lung inflammation and airway hyperresponsiveness (AHR) in asthma (effector phase). The complement components C3a and C5a levels are increased in the lungs of patients with asthma and are likely generated via the actions of both allergen and mast cell proteases. In vivo studies with rodents have shown that while C3a facilitates allergen sensitization in some models C5a inhibits this response. Despite this difference, both anaphylatoxins promote lung inflammation and AHR in vivo indicating that cells other than DC and T cells likely mediate the functional effects of C3a and C5a in asthma. This review focuses on the contribution of C3a and C5a in the pathogenesis of asthma with a particular emphasis on mast cells and basophils. It discusses the mechanisms by which anaphylatoxins activate mast cells and basophils and the associated signaling pathways via which their receptors are regulated by priming and desensitization. [Copyright &y& Elsevier]

Abstract: The impact of cellulose ethers (CE) on C3A hydration was examined to support the understanding of the retarding effect of CE on cement hydration. In this sense, we successively studied the CE adsorption on ettringite and calcium hydroaluminates, and then the CE influence during C3A hydration in presence or absence of calcium sulphate. We emphasized a phase-specific adsorption of CE depending on CE chemistry. Besides, in addition of CE, we highlighted a gradual slowing down of C3A dissolution as well as ettringite and calcium hydroaluminates precipitation. Again, a great impact of CE chemistry and CE adsorption behaviour were noticed. Thus, HECs induce always a stronger adsorption on calcium hydroaluminates and a longer C3A hydration delays than HPMCs. [Copyright &y& Elsevier]

Abstract: In the rat, C5a infusion mediates well-defined effects including hypotension and neutropenia. Conversely, the comparative effect of C3a in the rat is not yet defined. In the current study, we have investigated C3a receptor (C3aR) activation in the rat, using recombinant human C3a, the C3aR agonist WWGKKYRASKLGLAR, which is a C-terminal analogue of C3a, and a nonpeptide C3aR antagonist SB-290157, as pharmacological tools. In vitro, C3a and WWGKKYRASKLGLAR selectively bound to C3aRs and induced degranulation of C3aR-transfected RBL-2H3 cells. C3a or WWGKKYRASKLGLAR-induced degranulation was dose-dependently antagonized in a surmountable fashion by the nonpeptide C3aR antagonist. Intravenous infusion of C3a and WWGKKYRASKLGLAR to rats induced a rapid, transient and concentration-dependent hypertensive response, which was mediated by C3aR-induced prostanoid release. C3a and WWGKKYRASKLGLAR caused a small drop in circulating neutrophils, but a rise in circulating neutrophils was evident after 90–120 min. In contrast to C3a, C5a infusion resulted in hypotension, and rapid and transient neutropenia. These results demonstrate that C3a and C5a mediate distinct effects on blood pressure and circulating polymorphonuclear leukocytes in the rat. [Copyright &y& Elsevier]

Abstract: Objective: According to data from animal models, complement activation plays a major role in the brain injury after acute ischemic stroke. Scarce findings are, however, available on the detection of complement activation products in stroke patients. Methods: We have measured plasma levels of the five complement activation products (C1rC1sC1inh, C4d, C3a, C5a and SC5b-9) in samples of 26 patients with ischemic stroke upon admission. Twenty-six patients with severe carotid atherosclerosis served as patient controls. Results: Levels of two activation products (SC5b-9 and C4d)) were significantly elevated in the plasma of stroke patients, SC5b-9 levels, exhibited significant positive correlation with the clinical severity of stroke, the severity of neurological deficit, as well as with the level of functional disability. Conclusion: These findings suggest that complement activation plays an active role in the development of brain infarct. The measurement of complement activation products might help to determine the clinical prognosis after acute ischemic stroke. Furthermore, there is potential usefulness of complement modulating therapy in ischemic stroke. [Copyright &y& Elsevier]

• Effects of SF and NS on the hydration and hardening properties of C 3 A-gypsum systems were studied. • Sulfate attack resistivity improvement effects of SF and NS were determined. • Physiochemical features of SF and NS on their influences of C3A-gypsum systems were revealed. Micro- and nano-sized SiO 2 particles, i.e., silica fume (SF) and nanosilica (NS) have been extensively documented of improving the durability of concrete, but rare investigation on their specific effects on tri-calcium aluminate (3CaO·Al 2 O 3 , C 3 A) reactions/performances in harsh environment has been reported. This work determined the effects of SF and NS on the hydration and hardening properties of C 3 A-gypsum systems, and their performances under sulfate attack. Results showed that NS and SF can effectively improve the sulfate attack resistivity of the C 3 A-gypsum systems due to the filling effect and the reduction of crystal size/morphology-induced expansion: a significant reduction of the aspect ratio (length/diameter) can be observed in the NS-added sample comparing the pure C 3 A-gypsum system. Comparatively, SF can hardly change the morphology of ettringite (AFt), which could be due to that its bigger particle size cannot effectively block the ion migration. It is expected that these findings could contribute to the utilization of fine/ultra-fine SCMs in cementitious materials systems, especially those with high amount of aluminate phases. [ABSTRACT FROM AUTHOR]

Background: Peanut allergy is the most common food-related cause of lethal anaphylaxis and, unlike other food allergies, typically persists into adulthood. Resistance to digestion and dendritic cell activation by the major peanut allergen Ara h 1 are reported to contribute to its allergenicity. Objective: We sought to evaluate whether peanut molecules might also promote anaphylaxis through an innate immune mechanism. Methods: Naive mice were treated with a β-adrenergic receptor antagonist and long-acting IL-4 to increase sensitivity to vasoactive mediators and injected with peanut extract (PE). Shock was detected and quantified by means of rectal thermometry. Gene-deficient mice and specific antagonists were used to determine the roles of specific cell types, complement, Fc receptors, and vasoactive mediators in shock pathogenesis. Results: PE induces dose-dependent shock. PE activates complement in vivo in mice and in vitro in mice and human subjects. C3a and, to a lesser extent, stimulatory immunoglobulin receptors contribute to PE-induced shock. PE-induced shock depends more on macrophages and basophils than on mast cells. Platelet-activating factor and, to a lesser extent, histamine contribute to PE-induced shock. PE induces shock in the absence of the adaptive immune system. LPS contamination is not responsible for PE-induced shock. PE and IgE-mediated mast cell degranulation synergistically induce shock. Tree nuts have similar effects to PE, and skim milk and egg white do not. Conclusion: Peanuts can contribute to shock by causing production of C3a, which stimulates macrophages, basophils, and mast cells to produce platelet-activating factor and histamine. [Copyright &y& Elsevier]

The relationship between C3a-C3aR, IL-1β, and the acute exacerbation of chronic obstructive pulmonary disease is still unclear. This study aims to explore the expression levels of C3aR in peripheral blood WBCs and the concentrations of C3a, C3aR, and IL-1β in plasma in healthy controls and patients with chronic obstructive pulmonary disease (COPD). WBCs C3aR level in the peripheral blood, the concentrations of C3a, C3aR, and IL-1β in plasma were measured in 60 patients with acute exacerbation of COPD (AECOPD), 30 patients with stable COPD (SCOPD), and 30 healthy controls. The baseline characteristics and clinical data collected from enrolled patients, including age, gender, laboratory indicators, and lung function. We analyzed the correlation between C3a, C3aR, IL-1β, and lung function indicators (forced expiratory volume in the first second as a percentage of predicted value, FEV 1 %pred) in the AECOPD group. The white blood cell count (WBC), neutrophil/lymphocyte ratio (NLR), and C-reactive protein (CRP) of patients in COPD were higher than in healthy controls (P < 0.05). The peripheral blood WBCs C3aR mRNA and plasma C3a, C3aR, and IL-1β in AECOPD were higher than in SCOPD and healthy controls (P < 0.05). The peripheral blood WBCs C3aR mRNA and plasma C3aR, and IL-1β in AECOPD combined with respiratory failure were higher than in the non-respiratory failure group (P < 0.05). The peripheral blood WBCs C3aR mRNA and plasma C3a, C3aR, and IL-1β in AECOPD with high-risk were higher than in the low-risk group (P < 0.05). The peripheral blood WBCs C3aR mRNA and plasma C3a, C3aR, and IL-1β in AECOPD were negatively correlated with FEV 1 pred%. The peripheral blood WBCs C3aR mRNA, the plasma C3a and C3aR in AECOPD were positively correlated with IL-1β. The peripheral blood WBCs C3aR mRNA and plasma C3a, C3aR, and IL-1β in COPD patients were significantly related to the risk of disease deterioration. The C3a-C3aR axis may be involved in airway inflammation in patients with COPD. [ABSTRACT FROM AUTHOR]

Abstract: Eosinophils are blood and tissue immune cells that participate in a diverse range of activities normally beneficial for the host defense, but in circumstances of untoward inflammatory conditions these cells can be responsible for pathological responses. Accordingly the transit of eosinophils from the blood to tissues is a subject of considerable importance in immunology. In this article we review how the complement anaphylatoxins, C3a and C5a bring about eosinophil extravasation. These mediators do not merely provide a chemotactic or haptotactic gradient but are responsible for orchestrating innumerable responses by other cells types, including of endothelial cells, mast cells, and basophils in order to create an environment that is conducive for eosinophil infiltration. C5a has the capacity to prime the endothelium directly to present P-selectin, and C5a stimulated generation of eosinophil hydrogen peroxide and other oxidants can cause additional upregulation of endothelial P-selectin and ICAM-1. Moreover, the anaphylatoxins have the ability to recruit mast cells and basophils and can stimulate these cells to release IL-4 and IL-13, which by augmenting endothelial VCAM-1, convey some selectivity for eosinophils. The anaphylatoxins also have the capability to evoke the release and activation of eosinophil MMP-9, which is employed by this cell type to digest its way past the subendothelial matrix. Finally, because C3a and C5a can stimulate the generation of nitric oxide along with the secretion of histamine and LTC4 from several cell types, the anaphylatoxins can bring about an increase in vascular permeability that facilitates eosinophil accumulation at sites of allergic inflammation. [Copyright &y& Elsevier]

Abstract: The anaphylatoxins C3a and C5a are involved in the pathophysiology of microbial as well as allergic inflammation in the lungs. Besides their expression in leukocytes, receptors for C3a and C5a (C3aR and C5aR) have been noted in alveolar and bronchial epithelial cells, bronchial smooth muscle cells as well as in vascular endothelial and smooth muscle cells of normal and inflamed human and murine lungs. Recently, however, expression of anaphylatoxin receptors in parenchymal cells of the lung (and kidney) has been challenged. Using well-characterized monoclonal antibodies (mabs) against murine and rat anaphylatoxin receptors, we reexamined the pulmonary distribution of C3aR and C5aR. Immunohistochemistry was performed on frozen sections of lung tissues from normal mice and rats as well as from animals subjected to lipopolysaccharide (LPS)-induced inflammation or from MRL/lpr mice suffering from autoimmune disease. Furthermore, ovalbumin (OVA)-induced models of allergic asthma in the rat and mouse were investigated. Prominent expression of both anaphylatoxin receptors was detectable in resident as well as infiltrating leukocytes. No C3aR protein was observed in alveolar macrophages. Upon LPS- and OVA-challenge as well as in autoimmune inflammation, numbers of infiltrating leukocytes expressing prominent amounts of anaphylatoxin receptors increased. Even under these highly inflammatory conditions, however, expression of C3aR and C5aR was not inducible in parenchymal cells. Thus, our findings identify infiltrating leukocytes as a prominent source of anaphylatoxin receptors in inflamed lungs. A direct involvement of parenchymal cells in anaphylatoxin-mediated pulmonary inflammation is unlikely. [Copyright &y& Elsevier]

Abstract: The synthesis and structure–activity relationships against the C3a receptor of a series of substituted aminopiperidine derivatives are reported. DMPK properties and functional activities of selected compounds are described. The compounds obtained are the first non-arginine ligands of C3aR. [Copyright &y& Elsevier]

Abstract: The synthesis and in vitro binding of several new arginine-containing C3aR ligands are reported. DMPK properties and functional activities of selected compounds have been evaluated. One compound is shown to be active in an in vivo model of airway inflammation after aerosol administration. [Copyright &y& Elsevier]

Abstract: The aim of this study was to clarify whether the C3A content of cement had a significant effect on electrochemical chloride extraction (ECE) treatment efficiency. It is known that a higher C3A content in a cement gives it superior chloride complexing ability resulting in the formation of an “insoluble” calcium chloro aluminate compound. ECE was applied using cylindrical specimens made from concrete containing two levels of C3A (4.3% and 9.05%). Specimens were 5 cm in diameter and 10 cm in height. Steel was placed in the axial direction with an embedded length of 7 cm. These specimens were immersed in an NaCl solution and dried in a stream of air at 40 °C for 10 months. The corrosion was monitored by half-cell potential and polarization resistance measurements. After steel depassivation, ECE was applied for 20, 30, 40 and 50 days using a constant current density of 1 A/m2 of steel. At the end of the treatment, the specimens were maintained at 20 °C and 70% RH in order to observe the evolution of the steel (electrochemical measurements). The results show that, after 30 days of treatment, the chloride content remained constant in the specimen. This was probably due to OH− ion formation on the steel. The OH− ions “contribute” to the current transport, decreasing the ECE efficiency. Concerning the C3A content, ECE efficiency was slightly affected by C3A because only a part of the bound chloride ions was released. From the point of view of corrosion, half-cell potential showed a shift in the positive direction, indicating little corrosion activity at 20 °C and 70% RH. However, polarization resistance measurements showed that 2 months post treatment corrosion rates were significant, although the corrosion rate decreased from 6 μA/cm2 to 2.5 μA/cm2. [Copyright &y& Elsevier]

Abstract: Systemic activation of complement is a pathophysiological response common to severe disturbances such as hemorrhagic shock, major burn injury and sepsis. Intravenous infusion of cobra venom factor (CVF) has been used as an animal model of acute respiratory distress syndrome (ARDS), and reliably and selectively induces rapid intravascular activation of the complement system, leading to acute organ damage. In the present study, we have used different complement inhibitors to investigate the roles of complement products in CVF-induced responses in the rat. Rats were treated with either a C5a receptor antagonist (C5aRA, AcF-[OP(d-Cha)WR], 1 mg/kg i.v. or 10 mg/kg p.o.), a C3a receptor antagonist (C3aRA, N(2)-[(2,2-diphenylethoxy)acetyl]-l-arginine, 0.1 mg/kg i.v.) or a convertase inhibitor, rosmarinic acid (RMA, 10 mg/kg i.v.), prior to CVF-induced complement challenge. Intravenous CVF resulted in hallmark events evident in the development of ARDS, including systemic neutropenia followed by neutrophil migration to the lung and bronchoalveolar vascular leakage, blood pressure alterations, and an increase in TNFα levels in both serum and bronchoalveolar lavage fluid. These hemodynamic changes were differentially inhibited by antagonism of C5a receptors, C3a receptors or by inhibition of the entire complement cascade using RMA. This evidence strongly implicates complement factors in the development of lung injury associated with systemic complement activation and identifies complement inhibition as a potential therapeutic target for acute syndromes such as ARDS and other severe systemic shock states mediated by activation of complement. [Copyright &y& Elsevier]

Abstract: Anaphylatoxins are small molecules (∼9kDa) that are generated as a result of the activation of the complement system. These molecules play an important role in inflammation, and they are responsible for the activation of various innate and adaptive immune processes. The study of these important inflammatory molecules has been restricted to mammalian species so far. Recent studies have shown that teleost fish, unlike any other known animal species, contain multiple forms of the C3a anaphylatoxin, all of which are functionally active and play a prominent role in inducing superoxide production in fish leukocytes. The C5a anaphylatoxin has also been characterized in these animals, and like in mammals, it plays an important role in leukocyte chemotaxis and in triggering the respiratory burst of leukocytes. Interestingly, it has been shown that rainbow trout anaphylatoxins play an unexpected role in enhancing phagocytosis of particles. C5a and C3a receptors have recently been cloned and characterized in rainbow trout, suggesting that the duplication of these receptors from a common ancestor occurred before the emergence of teleosts. The studies derived from these molecules in teleost fish indicate that the basic structure and function of anaphylatoxins and their receptors, have been conserved for more than 300 million years. [Copyright &y& Elsevier]

Abstract: Introduction: Complement component C3 (C3) can be a target of pharmacological or toxicological agents. In the analysis of this, it is important to examine the involvement of fragments C3b and C3a since C3 function normally requires cleavage into these fragments. The present study describes a simple and efficient method for the preparation of rat complement C3b and C3a by using purified C3 and cobra venom factor (CVF) as a cleaving enzyme. Methods: CVF was purified from lyophilized cobra venom (Naja naja kausia) by two-step chromatography and was activated by incubation with human factors B and D. C3 was cleaved by incubation with activated CVF (CVF,Bb), and C3b and C3a were isolated by anion- and cation-exchange chromatography, respectively. Results: About 200 μg of CVF was purified from100 mg of cobra venom. All the CVF was activated by incubation with factors B and D. The C3b and C3a obtained were pure as analyzed by sodium dodecyl sulphate–polyacrylamide gel electrophoresis, and no digestive by-products such as C3f were found. Discussion: The advantage of the present method is that it is possible to prepare relatively large amounts of C3b by simple procedures without digestive by-products. C3a can be prepared from the flow through fraction of the C3b purification. C3b and C3a prepared by the present method would be useful for pharmacological or toxicological experiments involving receptor binding since their binding sites remain intact. [Copyright &y& Elsevier]

Abstract: The effect of different percentages of cement components (tricalcium aluminate C3A) on the corrosion of embedded reinforcing steel bars was studied in presence of 5% NaCl or 5% MgSO4 solutions. Different electrochemical techniques namely; half-cell potential measurement, impressed voltage method and impressed current method were used. The C3A in cement reduced greatly the corrosion of steel bars embedded in concrete subjected to chloride or sulphate solutions. In chloride solution, as the percent of C3A increased in cement from 2% to 10% the steel corrosion decreased proportionally. The rate of corrosion in 5% MgSO4 solution was decreased as the percent of C3A increased from 2% to 6%. From 6% to 10% the steel corrosion rate was rapidly accelerated. In general the presence of chloride and sulphate solutions in surrounding media reduced the destructive effect of sulphate ions on embedded steel bars. [Copyright &y& Elsevier]

Abstract: We have studied aspects of the molecular background to immune complement activation on solid surfaces. Quartz crystal microbalance with dissipation monitoring (QCM-D) sensor surfaces were modified by means of spin coating with polystyrene (PS) or sputtering of silicon dioxide (SiO2). The IC activation on modified QCM-D surfaces was investigated by incubation in serum, followed by determinations of the amounts of bound C3 fragments (C3c) at the surface. Determinations of soluble C3a and soluble C5b-9 complex (sC5b-9) were made with enzyme immunoassay (EIA) method. We found that IC activation was high on PS surfaces, independent of the method used for measurements. On the SiO2 surfaces, IC activation was generally lower, but still detectable with anti-C3c as well as sC5b-9 and C3a determinations. Pre-coating the surfaces with a layer of IgG resulted in that IC activation became very high on PS surface, while the IC response remained low on SiO2 surfaces. The lower level of IC activation on the SiO2 surfaces was explained by a low surface concentration of IgG as measured with QCM-D. This was a result of the high reversibility of the IgG protein adsorption as well as absence of sufficient conformational changes of adsorbed IgG molecules. The QCM-D method was as sensitive as the C3a and sC5b-9 determinations to reveal surface associated IC-activation on these model surfaces. Additional advantages of the QCM-D method are the broad dynamic measurement window, i.e. the high precision and the ability to perform time resolved measurements and the ease of making different surface modifications. [Copyright &y& Elsevier]

Activation of the complement system leads to cleavage of the C3 molecule into C3b and C3a fragments. The C3a fragment plays a major role in immunity by inducing chemotaxis of eosinophils and mast cells and stimulating the respiratory burst in leukocytes. Although this anaphylotoxin has been well studied in mammals, there is currently a lack of information about the structure and function of C3a anaphylotoxins in non-mammalian vertebrate species. Therefore, in the present study, we have isolated and characterized three different C3a anaphylatoxin molecules from rainbow trout, a teleost fish. C3a was generated from the trout C3-1, C3-3, and C3-4 isoforms by incubating each individual C3 molecule with purified trout factor B/C2 and factor D in the presence of Mg2+, then purifying the resulting C3a molecules by gel filtration. SDS-PAGE, N-terminal sequence and mass spectrometric analysis demonstrated the high degree of purity and expected molecular masses of the three C3a molecules. We showed that although activated trout serum was able to induce complement-dependent chemotaxis in trout head kidney leukocytes, none of the three isolated C3a molecules induced chemotaxis in the same cells. In contrast, all three C3a molecules strongly stimulated the respiratory burst of head kidney leukocytes in a dose-dependent manner. When the carboxy-terminal Arg was removed from all three C3a molecules, their ability to induce the respiratory burst was lost. These studies, therefore, provide strong evidence for the existence of three functional C3a molecules in a non-mammalian vertebrate species and suggest that some of the basic mechanisms of action of the C3a molecule have been conserved for more than 300 million years. [Copyright &y& Elsevier]